CVE-2023-6764

highpriority · track · 0EPSS 0.009 · 59 %ileDEEURUUS

grimoire priorityP2 · Scheduled

Exploitable?

—

no known exploitation

Likely / severe?

0.89% (59th) EPSS

CVSS 8.1 · high

Is it mine?

54 products

Check your exposure

Who says so?

5 sources

cnnvd · enisa_euvd · fstec_bdu · nvd

EPSS · scored 2026-10-27

A format string vulnerability in a function of the IPSec VPN feature in Zyxel ATP series firmware versions from 4.32 through 5.37 Patch 1, USG FLEX series firmware versions from 4.50 through 5.37 Patch 1, USG FLEX 50(W) series firmware versions from 4.16 through 5.37 Patch 1, and USG20(W)-VPN series firmware versions from 4.16 through 5.37 Patch 1 could allow an attacker to achieve unauthorized remote code execution by sending a sequence of specially crafted payloads containing an invalid pointer; however, such an attack would require detailed knowledge of an affected device’s memory layout and configuration.

cvss

Technical severity, 0–10. One row per scoring source.

8.1

010

base score 0–10 · higher = more severe · hover a vector to decode

v3.18.1highAV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:Hsecondary · FSTEC (BDU) RU

v3.18.1highCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:Hsecondary · ENISA EU

v3.18.1highCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:Hsecondary · security@zyxel.com.twexploitability 2.2 · impact 5.9

v3.17.4highCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:Usecondary · CVSS-BT (t0sche)

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Exploitation: none · Automatable: no · Technical Impact: totalcoordinatorcisa_ssvcUS

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-134USprimaryCWE-134US

affected products (54)

Products and version ranges known to be affected.

Zyxel ATP series firmware≤ version 4.32 through 5.37 Patch 1enisa_euvdEU
Zyxel ATP series firmwareall versionsenisa_euvdEU
Zyxel USG FLEX 50(W) series firmwareall versionsenisa_euvdEU
Zyxel USG FLEX 50(W) series firmware≤ version 4.16 through 5.37 Patch 1enisa_euvdEU
Zyxel USG FLEX series firmware≤ version 4.50 through 5.37 Patch 1enisa_euvdEU
Zyxel USG FLEX series firmwareall versionsenisa_euvdEU
Zyxel USG20(W)-VPN series firmwareall versionsenisa_euvdEU
Zyxel USG20(W)-VPN series firmware≤ version 4.16 through 5.37 Patch 1enisa_euvdEU
Zyxel Communications Corp. ATP4.32 → 5.37 Patch 1fstec_bduRU
Zyxel Communications Corp. USG 20(W)-VPN4.16 → 5.37 Patch 1fstec_bduRU
Zyxel Communications Corp. USG FLEX4.50 → 5.37 Patch 1fstec_bduRU
Zyxel Communications Corp. USG FLEX 50(W)4.16 → 5.37 Patch 1fstec_bduRU
zyxel atp100 firmware4.32 → 5.37nvdUScpe:2.3:o:zyxel:atp100_firmware:*:*:*:*:*:*:*:*
zyxel atp100 firmware= 5.37nvdUScpe:2.3:o:zyxel:atp100_firmware:*:*:*:*:*:*:*:*
zyxel atp100w firmware4.32 → 5.37nvdUScpe:2.3:o:zyxel:atp100w_firmware:*:*:*:*:*:*:*:*
zyxel atp100w firmware= 5.37nvdUScpe:2.3:o:zyxel:atp100w_firmware:*:*:*:*:*:*:*:*
zyxel atp200 firmware4.32 → 5.37nvdUScpe:2.3:o:zyxel:atp200_firmware:*:*:*:*:*:*:*:*
zyxel atp200 firmware= 5.37nvdUScpe:2.3:o:zyxel:atp200_firmware:*:*:*:*:*:*:*:*
zyxel atp500 firmware4.32 → 5.37nvdUScpe:2.3:o:zyxel:atp500_firmware:*:*:*:*:*:*:*:*
zyxel atp500 firmware= 5.37nvdUScpe:2.3:o:zyxel:atp500_firmware:*:*:*:*:*:*:*:*

showing 20 of 54

advisories (1)

Vendor and ecosystem advisories describing this.

WID-SEC-W-2024-0421Zyxel Firewall: Mehrere SchwachstellenDeutsch2024-02-19csaf · cert_bundDE
Ein entfernter Angreifer kann mehrere Schwachstellen in Zyxel Firewall ausnutzen, um einen Denial-of-Service-Zustand zu erzeugen oder beliebigen Code auszuführen.

also known as (4)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd fstec_bdu nvd cert_bund NVD CVE.org MITRE

published 2024-02-20modified 2026-06-17

related (781)

Related entries.

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+776 more

references (4)

External citations — patches, advisories, analysis.

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